Lipase from Candida sp.99-125 catalyzed ring-opening polymerization of e-caprolactone in the presence of 6-mercapto-1-hexanol was presented as a new metal-free approach for direct synthesis of welldefined thiol-terminated poly（e-caprolactone）.Remarkably,high chemoselectivity of lipase from Candida sp.99-125 toward hydroxyl and thiol was exhibited and quantitative thiol fidelity over 90% was achieved.The tedious protecting/deprotecting steps for thiol and metal residue were avoided.The polymerizations with around 70% monomer conversion were conducted in bulk and toluene at relative low temperature of 40 ℃.Number–average molecular weight of resulted polymers ranged from 3000 to4700 Da by changing the feed ratio between monomer and initiator.The structures of obtained thiolterminated poly（e-caprolactone） were demonstrated by combining NMR and SEC analyses.
Ning ZhuZi-Long ZhangWei HeXiao-Cheng GengZheng FangXin LiZhen-Jiang LiKai Guo
